Category Space Ship One

After a glide test, a rocket-powered flight, or a trip to space, SpaceShipOne made a horizontal landing on a runway like most other aircraft. As SpaceShipOne got ready to land, the pilot pneumatically actuated the nose skid and rear landing gear, as shown in figure 4.17.

A spring and gravity extended the nose skid into position. It had a maple wood tip that helped slow down the aircraft during landing. This unusual piece of landing gear also acted as a crush damper. Its simple design dramatically reduced the weight and complexity that is typical of retractable nose wheels.

The rear landing gear was also spring and gravity driven but had independent hydraulic brakes for each wheel. By fully depressing a rudder pedal, the brake engaged for the wheel on the corresponding side.

The aircraft was not equipped to retract the landing gear on its own. So, once the pilot put the landing gear down, the only way to get it back up was to land and let the ground crew reset it. There was a big, removable panel on SpaceShipOne’s belly where the rear landing gear is located that also provided access for ground support.

After resolving the avionics malfunction that caused the aborted glide flight, SpaceShipOne and White Knight were back up flying again the very same day. Melvill was dropped at 48,200 feet (14,690 meters) from White Knight flying at a speed of 105 knots. For his first maneuver, he put SpaceShipOne into a full stall to investigate stall characteristics.

The second maneuver was one of the most critical firsts of the entire flight test program. Evaluation of the feather would begin on this flight. The purpose of the feather was to decelerate SpaceShipOne during reentry into the atmosphere.

“That’s something you do in glide tests,” Burt Rutan said. “You don’t have to do that in spaceflight because once you decelerate from your spaceflight, you find yourself in a stable glide, which is identical to the way we flew the airplane on its first glide flight. So, we went out early in the program and put the feather up and put it down.”

Rutan had planned to do a high-speed pull-up in a glide flight and put the feather up as it peaked to simulate zero-g during the beginning of the program. But this turned out unnecessary and would have used up too much altitude. “We started off at 43,000 feet [13,110 meters] and put the feather up to make sure it flew the way we wanted,” Doug Shane said. “We ended up doing feather

Flight Test Log Excerpt for 5G

Date: 27 August 2003

Flight Number Pilot/Flight Engineer

SpaceShipOne 5G Mike Melvill

White Knight 32L Brian Binnie/Cory Bird

Objective: Same objectives as the aborted flight 31LC/4GC earlier today. Second glide flight of SpaceShipOne. Flying qualities and performance in the spaceship reentry or "feather" mode. Pilot workload and situational awareness while transitioning and handling qualities assessment when reconfigured. As a glider, stall investigation both at high and low altitude and envelope expansion out to 200 knots and 4 g’s. More aggressive, lateral directional characteristics including adverse yaw, roll rate effectiveness and control, including 360 degrees aileron roll, and full rudder side slips.

(source: Mojave Aerospace Ventures LLC, provided courtesy of Scaled Composites)

4________________________ J

deployments from tail-slide entries, and it just worked great. Everything was as good as we could have possibly hoped for.”

SpaceShipOne was gliding along at an airspeed of 90 knots when Melvill unlocked and activated the feather. As the tail booms began to elevate to their fully extended position of 65 degrees, the nose of SpaceShipOne pitched up but settled back to a near-level pitch. Melvill encountered a lot of buzzing and buffeting during the 70-second feathered descent.

With the feather deployed, SpaceShipOne dropped at a rate greater than 10,000 feet per minute [3,050 meters per minute]. However, it was extremely stable as it fell to the ground belly first.

“You could change the heading,” Mike Melvill said. “If you were pointing at Cal City, you could turn around and point it to Mojave. And you used the elevons to do that. It was kind of weird because normally it would roll, but your sensation was that it was yawing.”

“If you stepped on the rudders, it wasn’t perceptible to you what was happening. Nothing happened. The only thing that really did anything was lateral spin. It was kind of neat to go over and look at a different view, and look over there and see what was over there. We did that a lot when we were flying as a glider in the atmosphere.”

At 30,000 feet (9,140 meters) Melvill retracted and locked down the feather. SpaceShipOne was back as a glider, as shown in figure 7.6. He expanded the flight envelope for airspeed and g-force. And before landing, he executed SpaceShipOne’s first roll.

n November 6, 2004, the X Prize Foundation presented the Ansari X Prize trophy and the $10 million. Figure 10.1 shows Burt Rutan, Paul Allen, Mike Melvill, and Brian Binnie with members of the X Prize Foundation, Peter Diamandis, Gregg Maryniak, Amir Ansari, and Bob Weiss holding up the prize money. In order to also join in the celebration, Allen had flown the entire Scaled Composites team in one of his private airliners to the award ceremony held in St. Louis. Figure 10.2 shows the Scaled Composites team from an earlier photograph.

SpaceShipOne and the Ansari X Prize began on two separate but parallel courses. When they converged, their combined importance was greater than the sum of the two parts. It is difficult to imagine what the result would have been if SpaceShipOne or the Ansari X Prize had been taken out of the equation. Would another team have won the Ansari X Prize with the deadline and the funding set to expire in just a few months? Would the general public have had the awareness or been as involved to the degree that it was without the Ansari X Prize? Without the space mania would investors like Sir Richard Branson have embraced Rutan with such a sizable financial commitment?

The years 1996 to 2004 were very much a different time compared to the years 1919 to 1927. And although the Ansari X Prize was modeled after the Orteig Prize, it certainly was not a one-to-one substitution. At the end of the day, the X Prize Foundation did what they had to do to realize their dream. At the end of the day, Scaled Composites did what they had to do to realize theirs.

г л

Fig. 10.1. The Ansari X Prize trophy and $10 million check were presented on November 6, 2004, to Mojave Aerospace Ventures, the official partnership between Paul Allen’s Vulcan and Burt Rutan’s Scaled Composites. The photograph shows Bob Weiss, Gregg Maryniak, Amir Ansari, Peter Diamandis, Brian Binnie, Mike Melvill, Burt Rutan, and Paul Allen (left to right) at the award ceremony hosted in St. Louis. Mojave Aerospace Ventures LLC, photograph by Scaled Composite

V_________________ J

r ; ^

Fig. 10.2. In the Mojave Desert, which is referred to as the birthplace of the sonic boom, Scaled Composites, a small company founded by Burt Rutan in 1982, grew from an innovator in aircraft to an innovator in spacecraft. Without the efforts of the whole team, SpaceShipOne would never have been able to burst through Earth’s atmosphere and truly become a spaceship. Mojave Aerospace Ventures LLC, photograph by Scaled Composites

Ґ

Fig. 10.3. Influenced by the success of the Ansari X Prize, NASA announced the Centennial Challenges in 2005. John Carmack’s Armadillo Aerospace, an Ansari X Prize competitor, just missed winning the Lunar Lander Challenge in 2006. The lander, shown here, demonstrated vertical takeoff, hover, horizontal translation, and vertical descent, but it couldn’t stick the landing in the end. Dan Linehan

У

It is safe to say that those who have dreamed of someday flying into space had their chances become much, much better because of Rutan and the Ansari X Prize, whether it be on a ride in SpaceShipTwo with Virgin Galactic or in another suborbital spacecraft from a different spaceline.

One of the more distinguishing features of SpaceShipOne is its windshield, made of sixteen 9-inch- (23-centimeter-) diameter windows. The windows are small and round to keep the weight low and the structural strength high. Good visibility for the pilot flying SpaceShipOne, during all phases of the mission, was an important design consideration. This determined the arrangement of the windows.

With a slight tilt of the head, the pilot could always keep the horizon in sight. For one of SpaceShipOne’s rocket-powered flights, this proved crucial when the avionics display went temporarily blank. However, similar to the Spirit of St. Louis, the windows do not allow the pilot to see directly ahead of the spacecraft during landing.

Each window has dual panes and dual seals. This redundancy helped prevent loss of cabin pressurization in the case of damage to a window. The outer panes are 5/16-inch – (0.79-centimeter-) thick, heat-resistant Lexan polycarbonate. They are separated by a 1 /4-inch (0.64-centimeter) gap from 5/16-inch – (0.79-centimeter-) thick Plexiglas inner panes. There are small vent holes in the outer panes to help prevent the window from fogging up. The inner panes took all the pressurization and when loaded, could deflect 0.2 inches (0.5 centime­ters). Even if the inner panes failed, the leak rate would be very low, and SpaceShipOne could easily glide back home. Airliner windows also commonly use a two-pane construction with vent holes.

The crew entered SpaceShipOne through a 26-inch – (66-centimeter-) diameter, dual-sealed plug door on the port side. The door does not have an external handle but does have an internal handle that the crew could grab and pull out. Just like the plugs on the sides of the cockpit, it is shaped so that the pressure inside the spaceship held the door in place.

The spacecraft was not designed to have ejection seats, in order to help keep the cost, weight, and complexity at a minimum.

The nose cone was an escape hatch. Once it was unlocked, the pilot uses a handle near his left foot to turn the nose cone on its gear ring. After a clockwise turn of only 7.5 degrees, the nose cone detached and fell free from SpaceShipOne. Figure 4.18 and figure 4.19 both show views after the nose cone was detached. During an emergency egress, the

Ґ л

Fig. 4.18. A 36-inch (91-centimeter) opening reveals the cockpit after the nose cone twists off. The crew could use this opening or the 26-inch- (66- centimeter-) diameter plug-style door on the left side of the cockpit for emergency egress if necessary. Mojave Aerospace Ventures LLC, photograph by

David M. Moore

rudder pedals as well as most of the instruments are dragged out of the cabin by the nose cone, clearing a 36-inch – (91-centimeter-) diameter opening for the crew to crawl through. The crew then would have parachuted to safety after clearing SpaceShipOne.

The focus of the test flight program now began to shift to prepare for the upcoming rocket-powered flights. Up to this point, SpaceShipOne was flown light, but for rocket-powered flight, it would have to maneuver with a fully fueled rocket engine. SpaceShipOne was loaded so the center of gravity (CG), or the single balance point of SpaceShipOne s mass, moved to the aft to simulate these conditions.

When Melvill tested the stall characteristics for the aft-loaded SpaceShipOne, the nose swung upward uncontrollably before the wings reached the angle of attack at which they were expected to stall. SpaceShipOne entered into a spin while Melvill fought to regain control. Figure 7.7 shows SpaceShipOne as Melvill recovered from the tail stall.

“We had a pretty significant departure from controlled flight at high angle of attack, aft CG, due to a tail stall. That really was a big surprise,” Doug Shane said.

Г

Flight Test Log Excerpt for 6G

Date: 23 September 2003

Flight Number Pilot/Flight Engineer

SpaceShipOne 6G Mike Melvill

White Knight 37L Pete Siebold/Matt Stinemetze

and Jeff Johnson

Objective: Third glide flight of SpaceShipOne. Aft CG flying qualities and performance evaluation of the spaceship in both the glide and reentry or "feather" mode. Glide envelope expansion to 95 percent airspeed, 100 percent alpha [angle of attack] and beta [sideslip angle], and 70 percent load factor. More aggressive post-stall maneuvering and spin control as a glider and while feathered. Nitrous temperature control during climb to altitude and performance of upgraded landing gear extension mechanism and space-worthy gear doors.

(source: Mojave Aerospace Ventures LLC, provided courtesy of Scaled Composites)

4___________________ J

Г ‘

Fig. 7.6. After quickly correcting the avionics malfunction, SpaceShipOne and White Knight returned to the air several hours after the aborted fourth test flight.

During this flight test, SpaceShipOne extended its feather for the first time. It performed superbly. Mojave Aerospace Ventures LLC, photograph by David M. Moore

v____ J

Г

Fig. 7.7. The sixth glide flight, on September 23, 2003, focused on the handling qualities when SpaceShipOne was loaded in the back, where the heavy rocket engine would eventually be. SpaceShipOne stalled unexpectedly, and the photograph shows the craft right after recovery.

Mojave Aerospace Ventures LLC, video capture provided courtesy of Discovery Channel and Vulcan Productions, Inc.

ч___________________________________________________________________________________ У

The feather wasn’t raised during the test flight, but during the climb to release altitude, the pressure test of the oxidizer tank revealed a variation of less than 6 psi. This meant that the temperature of the nitrous oxide inside could be controlled very well by exhaust air ducted in from White Knight.

Scaled Composites needed wind-tunnel data to evaluate the problem with the tail booms. “Except we didn’t have a wind tunnel, but we did have a pickup truck. And we had our aero guy, Jim,” Shane said.

Using a converted pickup truck fitted up with instrumentation, called the Land Shark, engineers aerodynamically tested mockups of the tail boom. With clearance from Mojave Airport, the Land Shark zoomed up and down a runway to collect data.

“We finally ended up doing a fence and a span increase on both the stabilizer and the elevon and resolved the problem,” Shane said.

A triangular strake was also added to each tail boom, right in front of each horizontal stabilizer. SpaceShipOne was ready to go back to flight testing.

r—————————————– Л

Flight Test Log Excerpt for 7G

Date: 17 October 2003

Flight Number Pilot/Flight Engineer

SpaceShipOne 7G Mike Melvill

White Knight 38L Pete Siebold/Cory Bird

and David Moore

Objective: Fourth glide flight of SpaceShipOne. Primary purpose was to examine the effects of horizontal tail modifications at both forward and mid-range CG locations (obtained by dumping water from an aft ballast tank between test points). The tail modifications included a fixed strake bonded to the tail boom in front of the stabilator and a span-wise flow fence mounted on the leading edge of each stab at mid-span. Other test objectives included a functional check of the rocket motor controller, ARM,

FIRE, and safing switches as well as the oxidizer dump valve. Additional planned maneuvers included full rudder pedal sideslips and more aggressive nose pointing while in the feathered configuration.

(source: Mojave Aerospace Ventures LLC, provided courtesy of Scaled Composites)

V___________________ J

As the involvement and development of the commercial space indus­try continues to move forward and expand, many new ideas and designs are being introduced to the public. Even NASA has gotten into the spirit of public and commercial spaceflight. In 2005, the agency announced the first two cash prizes in a series called Centennial Challenges: the space tether and beam-power challenges,
which are both the components needed to build an elevator to space. In 2006, the less obscure lunar lander challenge was added, and other challenges soon followed.

NASA has partnered with the X Prize Foundation to run some of the Centennial Challenges during the annual X Prize Cup. Figure 10.3 shows the lunar lander of John Carmack’s Armadillo Aerospace, a team that had competed for the Ansari X Prize, whose amazing demonstration missed winning the challenge in 2006 by the slimmest of margins.

The X Prize Cups are a cross between air shows and space expos, where companies show off and, in some cases, even demonstrate many of the latest and greatest ideas. One of the big attractions is the Rocket Racing League, which is still in development.

Sean D. Tucker, a champion aerobatic pilot who is looking forward to flying in the league, said, “It is going to be very similar to a Red Bull course except longer and higher, and I think there are going to be milestones in the sky and altitudes you have to hit in the sky as well and then come back down. I think it is going to be a truly three-dimensional course, They’re working with the technology now to have heads-up displays where you can see the virtual course in the air.” Figure 10.4 shows a prototype rocket racer.

As recently as 2001, Dennis Tito became the first paying space tourist, flying to the International Space Station aboard a Russian Soyuz. Since then, four others have made this $20 million, or more, journey. In 2006, Anousheh Ansari was doing research based upon
this type of spaceflight for a venture she was involved with. She said, “I was looking into it to find out what type of training was really required if we were to commercialize orbital flights. Do people real­ly need six months of training and all these things? The best way to find out was to go through the program. I started training as a back­up. But three weeks before the flight the primary crewmember got ill. He failed one of his medical tests. And that’s when they said, ‘Well, if you want to go, you can go. You can take that seat now.’ And I just couldn’t say no to that.”

Figure 10.5 shows Ansari floating about in the International Space Station. She skipped over suborbital entirely and went straight to orbital. With Ansari’s support, she helped open the door to space a

Ґ л

Fig. 10.5. Space tourism began in 2001 when Dennis Tito rocketed to the International Space Station in a Russian Soyuz. In 2006, Anousheh Ansari joined the handful of people who have made this same journey. At between $20 million and $40 million, this ticket is out of reach from most people.

But a growing number of entrepreneurs are recognizing that there is not just a desire for space but a demand for space. Prodea Systems, Inc. All rights reserved. Used under permission of Prodea Systems, Inc.

v____________________________________________________________________________________________ )

little wider for the rest of the public. This unexpected opportunity for her was well deserved.

One of the bigger prizes still out there is the $50 million America’s Space Prize announced in 2004 by Bigelow Aerospace, which is an orbital version of the Ansari X Prize. In 2007, the X Prize Foundation raised the ante, not in terms of money but in terms of miles. Partnering with Google, the $30 million Google Lunar X Prize will have teams compete to land on the Moon. This is a
one-way ride, though. No self-replicating, carbon-based life forms are required for the trek. But before orbital or lunar spaceflights get going for the public, there is still another race on for suborbital flights. About a dozen companies are currently developing suborbital spacecraft, several of which were Ansari X Prize competitors, like Starchaser and the da Vinci Project. The truth is, there is an enormous amount of activity behind the scenes as well as on center stage.

Because SpaceShipOne slowed down so quickly, it did not experience extreme temperatures very long. Therefore, thermal loads were much smaller than those faced by the Space Shuttle. SpaceShipOne required only a relatively simple thermal protection system (TPS). Its TPS design consisted of two main parts.

The first part was built in during the manufacture of the composites. When the composite skins for the areas that would experience high temperatures during reentry were constructed, instead of

epoxy, a phenolic resin was used with the carbon fiber. The temperature tolerance for these composites increased by 50 to 70 degrees Fahrenheit.

About 14 pounds (6.4 kilograms) of an approximately 0.035-inch – (0.09-centimeter-) thick ablative coating developed by Scaled Composites was added to 25 percent of the surface of SpaceShipOne as the second part of the TPS. Ablative coatings made of reinforced plastic have been around since the early space program. The ablative process reduces the temperature of a spacecraft’s surface that faces the airstream on reentry by absorbing some of the heat that is generated. The heat absorbed causes the ablative coating to burn free of the spacecraft, so, in effect, the coating carries away a portion of the heat when it flies off the spacecraft.

When the ablative coating burns, it undergoes a chemical reaction. The heat provides the energy needed for this chemical reaction to

г ^

Fig. 4.20. Wax stripes were added to the various surfaces exposed to heating during reentry. These surfaces already had a red-colored coating that was part of the thermal protection system (TPS). Each colored wax stripe on the right wingtip, as shown here, melted at a different temperature. By studying the remaining wax after a flight, engineers could determine a heating profile. Mojave Aerospace Ventures LLC, photograph by David M. Moore

V_____________________________________ J

occur. Therefore, the heat absorbed during the ablation process is heat that is no longer available to heat up SpaceShipOne. The abla­tive coating is then reapplied for the next spaceflight. Figure 4.20 shows the temperature effects on a wingtip and its colored wax test stripes.

Even in the worst-case scenario where the TPS was completely gone, the fuselage could have withstood the damage and returned the crew unharmed. Because of the short duration and relatively low altitude of the spaceflight, SpaceShipOne was not equipped with radiation shielding.

“A stall is when the air flowing over the wing no longer stays attached to the surface. It’s not developing any lift anymore. And as soon as it stalls, you are not an airplane anymore. You are just a 2,000-pound [910-kilogram] lump falling out of the sky,” Mike Melvill defined in Black Sky, the Discovery Channel documentary about SpaceShipOne.

For this flight, the only modifications to each tail boom were the addi­tions of the strake and flow fence. The enlargement of the horizontal stabilizers would wait until the next test flight. However, the new mod­ifications did improve the aerodynamics, and the uncommanded pitch-up of the nose at aft CG was eliminated. Melvill was able to then turn his attention to the feather and rocket-engine controls. Figure 7.8 shows the feather deployed as he continued to push maneuverability limitations.

After the functionality of the rocket-engine instruments and controls checked out, Melvill was ready to land. Figure 7.9 shows a view from the camera mounted in his helmet as SpaceShipOne neared the runway. The glide flight lasted 17 minutes and 49 seconds.

Ґ ^

Fig. 7.8. Several modifications were put in place to address the stall problem encountered in the previous flight, including the addition of a triangular strake mounted in front of each horizontal stabilizer and a flow fence attached midspan on each horizontal stabilizer. Mojave Aerospace Ventures LLC, video capture provided courtesy of Discovery Channel and Vulcan Productions, Inc.

V___________________ J

г ^ ^

Fig. 7.9. Flying the first six piloted flights, two captive carries, and four glide flights, Mike Melvill continued to expand the flight envelope. Step by step, he pushed SpaceShipOne to perform a little harder so the engineers could get a more complete picture of its flying qualities. Mojave Aerospace Ventures LLC, video capture provided courtesy of Discovery Channel and Vulcan Productions, Inc.

V____________________________________________________________ )

Based on the design and trajectory of SpaceShipOne, now a proven space­ship, SpaceShipTwo takes advantage of the lessons learned while flying SpaceShipOne. Rutan stated his commitment to making it one hundred times safer than anything that has previously carried people to space.

On September 27, 2004, just days before the first Ansari X Prize flight attempt, entrepreneur Sir Richard Branson, founder ofVirgin Records and Virgin Atlantic, entered into an agreement with Paul Allen and Burt Rutan to build a fleet of SpaceShipTwos to be launched from carrier aircraft similar to White Knight. SpaceShipTwo is about three times the size of SpaceShipOne, and its carrier is as large as an airliner. Figure 10.6 shows a conceptual drawing of SpaceShipTwo and its carrier aircraft, and figure 10.7 shows a size comparison that includes SpaceShipOne and SpaceShipTwo.

Branson formed the spaceline Virgin Galactic, in which he desig­nated the first SpaceShipTwo the Virgin Spaceship (VSS) Enterprise after Star Trek’s famed spaceship, and the carrier aircraft Eva after his mum. Virgin Galactic will pay $250 million for a fleet containing five

SpaceShipTwos and two White Knight Twos. True to Rutan fashion, the program to develop these aircraft, called Tier lb, is top secret.

The trajectory is a basic up and down, like SpaceShipOne s, but initial launches will likely take place where the carrier aircraft flies from Mojave out over the Pacific Ocean, as shown in figure 10.8. SpaceShipTwo then reenters the atmosphere after having reached a reported apogee of 84—87 miles (135—140 kilometers), whereas during SpaceShipOne’s final flight it hit 69.6 miles (112 kilometers), well above the Ansari X Prize limit of 62.1 miles (100 kilometers). Having a better glide range than its predecessor, SpaceShipTwo will take a scenic glide back to Mojave.

SpaceShipTwo will have two pilots and room for six passengers. The price for the 2.5-hour trip will be about $200,000 to start with, which includes an orientation flight where the passengers on deck get to watch an actual flight of SpaceShipTwo from the carrier aircraft. That hefty price tag will come down once the economy of scale and competition begin to take hold. Virgin Galactic released mockups of the interior in September 2006. As shown in figure 10.9, passengers

ґ

Fig. 10.6. An early conceptual design of SpaceShipTwo and White Knight Two shows the similarities to their predecessors. However, SpaceShipTwo will be three times the size of SpaceShipOne and has a cabin the size of a Gulfstream 4 corporate jet while White Knight Two will be larger than a Boeing 757. Virgin Galactic’s initial fleet will include five SpaceShipTwos and two White Knight Twos. Courtesy ofVirgin Galactic

ґ

Fig. 10.8. This conceptual diagram shows an early representation of SpaceShipTwo’s flight profile based on the flight profile of SpaceShipOne. SpaceShipTwo will be three times as large as its predecessor but will share many of the same design elements. Courtesy of Virgin Galactic

к______________________________________________________________________________________

will be able to release their seatbelts and float around inside the cabin during a weightlessness period of about four minutes.

The conceptual drawings and early flight specifications available to the public will undoubtedly differ a bit from the end results. The launch altitude of 60,000 feet (18,290 meters) that has been floating
around, for example, is a number that will likely come down. Just because the vehicles are larger and apogee is planned to be higher doesn’t necessarily mean everything else scales up, too. After all, SpaceShipOne was planned to launch at 50,000 feet (15,240 meters), dropped to 48,000 feet (14,630 meters), and then finally ended up

ґ ; л

Fig. 10.9. A mockup of SpaceShipTwo’s cabin interior was revealed in 2006. Six passengers will ride to space, and when they get there, they will be able to unbuckle their seatbelts and float around the cabin to enjoy the weightlessness and the view. Courtesy of Virgin Galactic

V__________________________________________ J

at 47,000 feet (14,330 meters). To turn the corner with that big rocket engine blaring, SpaceShipTwo still needs air for the control surfaces to bite into, right? Will SpaceShipTwo even be mounted underneath the carrier aircraft, or will it ride on top like the Space Shuttle on a 747? Why risk your spaceship if your carrier aircraft has a landing gear failure? Why waste energy pulling downward away from the carrier aircraft during separation? However, a carrier aircraft could fly to a higher altitude in order to reduce the fuel requirements of a top-launching spacecraft if the carrier aircraft was able to pitch up and begin turning the corner for the spacecraft prior to separation.

SpaceShipTwo is set to fly passengers in the 2008—2009 time – frame. But before flight testing begins, SpaceShipTwo will be unveiled. SpaceShipThree will eventually follow. It will be the first of Rutan’s Tier Two vehicles, designed for Earth orbit. SpaceShipThree certainly has a model number by now.

Clean, dry air was used in the pneumatics to pressurize the actuators. The cabin was also pressurized with air. Each system had its own high-pressure bottle and a backup bottle. The feather, environmental control system (ECS), and reaction control system (RCS) each had a bottle A and bottle B. The initial pressure of these six bottles was 6,000 pounds per square inch (psi). Other systems also required pressurized air, but they fed off of these bottles. Electricity was provided by an array of lithium batteries.

SpaceShipOne was the first manned spacecraft to use a hybrid rocket engine, which is a cross between a liquid-fueled rocket engine and a solid – fueled rocket engine. Designed by Scaled Composites, it ran by using a combination of synthetic rubber and nitrous oxide. Mojave Aerospace Ventures LLC, photograph by David M. Moore